Here is a list of scenes + scene length for Peaky Blinders opening episode.

It also shows which characters are in each scene.

The hero is Thomas Shelby. His scenes are highlighted in red.

1. 0.18 Chinese Man and Girl.
2. 1.00 Thomas + extras.
3. 1.05 Thomas + Chinese Man + Girl.
   
4. 1.35 Thomas + various (opening credits).
5. 0.17 Thomas.
6. 0.30 Thomas + Finn.
7. 0.52 Thomas + John.
8. 1.28 Thomas + Arthur.
9. 0.54 C.I Campbell.
10. 1.21 Freddie Thorne + workers.
11. 0.22 C.I Campbell.
12. 0.18 Thomas.
13. 4.33 Thomas + Freddie Thorne + Danny.
14. 0.10 C.I Campbell.
15. 0.57 Aunt Polly + John Shelby.
16. 1.52 Thomas + Polly + Arthur + The Shelby Family.
17. 1.02 Jimmy Jesus + C.I Campbell + extras.
18. 3.11 Polly and Thomas.
19. 0.38 Thomas + Ada (transition).
20. 1.35 Ada and Freddie.
21. 0.24 Grace.
22. 2.01 Grace + Harry the barman
23. 3.49 Campbell + police.
24. 0.46 Arthur + police.
25. 3.28 Campbell + Arthur.
26. 1.21 Grace + Thomas + Barman.
27. 1.43 Aunt Polly + Arthur.
28. 0.07 Ada.
29. 1.01 Grace + Thomas.
30. 1.14 Freddie + Ada.
31. 2.09 Thomas (war dream sequence.)
32. 0.45 Danny + Italian butcher.
33. 0.15 Campbell.
34. 1.46 Campbell + Winston Churchill.
35. 2.04 Thomas + Uncle Charlie
36. 0.17 Campbell.
37. 1.53 Campbell + Grace
38. 4.03 Thomas + Danny.
39. 1.10 Arthur + Thomas.
40. 1.14 Danny and Uncle Charlie.
41. 0.18 Aunt Polly + Thomas.
42. 0.36 Thomas + Grace

3 things to note.

1. Thomas is in 7 of the opening 8 scenes.

2. In total, Thomas is in 20 out of 42 scenes (approximately 50%).

3. Thomas is on screen for 27.21 minutes (the episode runs at 56.12 so again approximately 50%).

How long is your hero on screen for?